neo-go/pkg/core/mpt/helpers.go
Evgenii Stratonikov dc6741bce7 mpt: implement MPT trie
MPT is a trie with a branching factor = 16, i.e. it consists of sequences in
16-element alphabet.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
2020-07-30 12:42:15 +03:00

35 lines
681 B
Go

package mpt
// lcp returns longest common prefix of a and b.
// Note: it does no allocations.
func lcp(a, b []byte) []byte {
if len(a) < len(b) {
return lcp(b, a)
}
var i int
for i = 0; i < len(b); i++ {
if a[i] != b[i] {
break
}
}
return a[:i]
}
// copySlice is a helper for copying slice if needed.
func copySlice(a []byte) []byte {
b := make([]byte, len(a))
copy(b, a)
return b
}
// toNibbles mangles path by splitting every byte into 2 containing low- and high- 4-byte part.
func toNibbles(path []byte) []byte {
result := make([]byte, len(path)*2)
for i := range path {
result[i*2] = path[i] >> 4
result[i*2+1] = path[i] & 0x0F
}
return result
}